LaTeXiT: create latex formulae to drag and drop

LaTeXiT is a fantastic application: it allows you to input a LaTeX formula, compile it with a single click, and obtain an image that you can drag and drop pretty much everywhere (an existing LaTeX presentation or a plot for instance).

Important: LaTeXit is not yet packaged for Leopard. If you are a Leopard user, then do not install LaTeXiT 1.14.4, but go for LaTeXiT 1.14.3 instead. More about it later.
Update: LaTeXit 1.15.0 has just been released. This version is Leopard-compatible (thanks Bjorn Sandstede).